With this series we’ll try to demolish the wall of misconceptions which separates people from the truth. Articles of the series will cover internationally relevant topics. The second part deals with biodegradable plastics (read the first part here). Written by Noémi Szabó.

The truth: on one hand, we use these, too, as disposable plastics (so they don’t reduce plastic waste generation at all). On the other hand, their management (i.e. compostation) is not yet solved in Hungary, and it only works abroad in case of proper sorting. Therefore biodegradable plastics cannot be considered environmentally friendly products.

Bioplastics

Biobased plastics, i.e plastics that are made of base materials that contain biogenic carbon (although the product can be polyethylene or biodegradable materials) and biodegradable plastics are collectively referred to as bioplastics.

Also, there are oxo-degradable plastics that do not actually decompose, but only disintegrate into microplastics.

Breakdown by degradation

1. Biodegradable plastics: plastics that can be converted into water, carbon-dioxide and biomass. Degradation time is heavily influenced by environmental factors like temperature and humidity. The most widely used biodegradable plastic, made out of highly starchy vegetables, is PLA (polylactic acid), which can be degraded under special industrial conditions.2. Compostable plastics: plastics that will biodegrade at least 90% within 180 days in an industrial or municipal composting facility, and their leftover compost doesn’t contain harmful components.3. Oxo-degradable plastics: conventional plastics mixed with additives that facilitate fragmentation. Exposed to oxygen, heat, and humidity, they gradually disintegrate, but at the end of the process the resulting microplastics can linger in the environment for a very long time before eventually fully breaking down.

Problems with PLA

As I’ve already mentioned, PLA will only degrade at high temperatures and over several months, which means that only industrial composting is feasible, household composting isn’t. For this to work, however, it would be necessary to establish a system in Hungary for collecting organic household waste, and PLA would have to be sorted as well. “In Budapest, only 10% of household waste is sorted, and only half of that can be recycled.” – said the representative of the Hungarian Waste Management Federation during the 2019 Green National Meeting (read more about the Green OT here). Since most Hungarians still cannot sort their waste properly, contaminated and inappropriate materials end up among sorted recyclables.

PLA must not be sorted together with plastic waste, as it harms recyclate quality (if not spotted and removed during further sorting). Establishing proper sorting routines is further complicated by material designation often missing from PLA products, making them easy to confuse with regular plastics.

Source: flickr.com

The other problem: since it’s not fully compostable, PLA only increases the number of disposable plastics. In addition, upon seeing products labeled as biodegradable or compostable, people are more likely to discard them, thinking that they do no harm to the environment. This doesn’t help spread the environmentally friendly notion of buying fewer plastic products and reusing the existing ones several times.

When does it make sense to use biodegradable plastics?

When reuse is by no means feasible (e.g. in healthcare), but even then, proper sorting is to be taken care of. Or if sorting of these products would be established in Hungary, too. There are a number of good examples of this abroad. For example, in Italy, household organic waste is collected in PLA bags, so they can be composed together (also, cloth diapers are so widespread – even in daycares – that there is demand for businesses that collect, transport, and wash these diapers).